The separation of gas from fluids in all types of wells has been a problem for over a century as evidenced by U.S. Pat. No. 47,011. Submersible pumps both in water and oil wells have had operating problems with gas-containing liquids, as taught in U.S. Pat. No. 2,158,393 and 4,330,306. In oil wells, the typical solution has been to pass the gas laden liquid through a mesh screen which traps the gas bubbles while passing the fluid, as exemplified in the last-mentioned patent.
In water wells, there are frequently multiple water-bearing stratas at various depths in a well. The water enters the well casing through perforations in casing adjacent the gravel stratas and falls to the bottom of the well where a turbine pump is located to raise the water to the surface. The level of the sump or pumping level is quite often hundreds of feet below the producing level and the fall to the sump of the well causes the water to entrain a substantial amount of air which interferes with the operation of any turbine type of pump.
One solution to this problem has been to drill a substantially oversized hole from that of the casing, and then fill the hole surrounding the casing with sized gravel which sufficiently slows the downward movement of the water to the sump of the well to allow the air to rise and separate before the water is drawn into the intake pump. This solution is obviously quite expensive since it entails large well holes of diameters up to 24 inches.
Another solution to this problem is shown in previously mentioned U.S. Pat. No. 2,158,393 which also involves drilling an expensive over-sized hole. In this system, a supplemental casing is positioned outside the main casing surrounding the water-bearing strata with separate small diameter pipes connecting the supplemental casing to the sump of the well so that the water passing therethrough is in a solid column without air bubbles or pockets. To achieve a solid column of water passing from the producing strata to the sump, it is difficult to achieve with varying flow rates from the strata, as evidenced by the necessity of manually-operated ball valves 17 in the last-mentioned patent.